In conventional head space sample analysis, a liquid or solid sample is contained in a vial that is connected to a head space sampling device. The head space sampling device is used to sample the head space above the sample within the vial. Often, the sample is heated to produce a vapor that fills the head space. Prior to sampling of the head space, the vial is often pressurized with a gas that is provided to the vial in a controlled manner. For example, the vial typically can be pressurized by a gas until a selected pressure is reached. When desired pressure characteristics are present within the head space sampling device, the gas from the head space can be directed toward a head space analyzer. Thus, the success of conventional head space analysis systems relies on precisely controlled gas pressures and/or gas flow rates, which help to direct the sampling process. In particular, the presence of leaks within these head space analysis systems can significantly reduce the accuracy and value of any results produced by the systems.
Despite the need for precise control and monitoring of gas pressure and flow rate within conventional head space analysis systems, the leak tests within these systems typically have limited effectiveness. In general, most conventional leak tests either cannot function in an automated manner or are only capable of detecting leaks under particular conditions. For example, many conventional leak tests require specific pressure or temperature conditions or are limited to analysis of specific types of samples. Additionally, many conventional leak tests are only run as part of preventative maintenance procedures rather than as an integral part of individual sample analysis. Furthermore, conventional leak tests generally are only capable of detecting large leaks, thereby allowing more minor leaks to continue throughout sample analysis. Although some dynamic leak test mechanisms do exist, these leak testing mechanisms require specific calibration for each different sample type, each different sample size, and each set of particular pressurization conditions. Most conventional leak tests also are not capable of detecting leaks within the vial containing the sample.
Accordingly, there is a need in the pertinent art for automated and programmable methods for simultaneously detecting leaks of all sizes within a head space analysis system and within a vial containing a sample prior to analysis of the sample. There is a further need in the pertinent art for automated and programmable methods of detecting leaks within a head space analysis system under a variety of pressure conditions and without requiring specific calibration for each sample to be analyzed.